The present proposal is an application for continuation of an on-going program on the purification of human urinary erythropoietin. Crude human urinary erythropoietin is being provided by the Blood Resources Division, National Heart, Lung and Blood Institute and will be purified upwards of 10,000 units/mg utilizing purification techniques for glycoproteins in the Laboratory of Hematopharmacology, Department of Pharmacology and the Laboratory of Glycoprotein Chemistry, Department of Biochemistry at Tulane University School of Medicine. The techniques to be used to continue the work on purification of erythropoietin are a modification of those described in the original application and involve the use of solubilization in phosphate buffer, phenol-PAS treatment, sepharose-blue affinity chromatography, wheat germ lectin affinity chromatography, Conconavalin-A chromatography, sephacryl S-200 and slab gel electrophoresis. We will continue to use the exhypoxic polycythemic mouse assay (Fe59 incorporation in red cells) to monitor the eluates and fractions at each step in the purification scheme. Determinations of molecular weight, amino acid composition and identification of the sugar residues will be carried out on the erythropoietin purified to homogeneity. Partially purified fractions with specific activity at least 5,000 units/mg will be sent to the Blood Resources Division of the National Heart, Lung and Blood Institute for distribution.